U.S. patent application number 10/369589 was filed with the patent office on 2004-08-26 for non-contact aerodynamic diverter/stacker insertion system.
Invention is credited to Mayerberg, Willson L. II, White, Randall E..
Application Number | 20040164480 10/369589 |
Document ID | / |
Family ID | 32868086 |
Filed Date | 2004-08-26 |
United States Patent
Application |
20040164480 |
Kind Code |
A1 |
Mayerberg, Willson L. II ;
et al. |
August 26, 2004 |
Non-contact aerodynamic diverter/stacker insertion system
Abstract
Objects such as pieces of mail are stacked without significant
contact therewith by producing laminar air flow over a surface
which defines or parallels a desired movement path for the objects.
The objects are placed and form a barrier between the laminar air
flow and ambient air and movement such as turning an edge of the
object to prevent impact on other objects and regulation of
direction velocity an kinetic energy of the motion of the objects
is regulated by the Coanda effect of the laminar flow. The object
thus provides an acoustic barrier to reduce generation and
propagation of noise by the high pressure air used to create the
laminar flow. An air amplifier reduces the volume of high pressure
air required to provide control of object motion.
Inventors: |
Mayerberg, Willson L. II;
(Skiatook, OK) ; White, Randall E.; (Owego,
NY) |
Correspondence
Address: |
WHITHAM, CURTIS & CHRISTOFFERSON, P.C.
11491 SUNSET HILLS ROAD
SUITE 340
RESTON
VA
20190
US
|
Family ID: |
32868086 |
Appl. No.: |
10/369589 |
Filed: |
February 21, 2003 |
Current U.S.
Class: |
271/195 ;
271/207; 271/211; 414/903 |
Current CPC
Class: |
B65H 2406/111 20130101;
B65H 2301/4214 20130101; B65H 29/52 20130101; B65H 31/06 20130101;
B65H 2701/1916 20130101 |
Class at
Publication: |
271/195 ;
414/903; 271/207; 271/211 |
International
Class: |
B65H 029/24 |
Claims
Having thus described my invention, what I claim as new and desire
to secure by Letters Patent is as follows:
1. A stacker apparatus comprising a plate having a curved portion,
means for producing a laminar flow of air over said curved portion
of said surface and directed along a path of desired object
movement, means for directing an object along said laminar flow of
air whereby motion of said object is regulated along said path of
movement by said laminar air flow.
2. A stacker as recited in claim 1, wherein said means for
producing a laminar flow of air includes an air knife.
3. A stacker as recited in claim 1, wherein said means for
producing a laminar flow of air includes an air amplifier.
4. A stacker as recited in claim 2, wherein said means for
producing a laminar flow of air includes an air amplifier.
5. A stacker as recited in claim 1, further including a valve for
controlling said means for producing a laminar flow of air.
6. A stacker as recited in claim 5, wherein said valve is
controlled responsive to a sensor.
7. A stacker as recited in claim 1, wherein said means for
producing laminar flow is divided into sections across the width of
an article path.
8. A stacker as recited in claim 7, wherein respective one of said
sections of said means for producing laminar flow are selectively
controlled.
9. A stacker as recited in claim 8, further including means for
sensing dimensions of an article to perform said selective control
of said respective sections.
10. A stacker as recited in claim 9, further including a sensor for
controlling said means for producing said laminar flow in
accordance with detection of a said object.
11. A method of controlling movement of an object, said method
comprising steps of directing a laminar flow of air along a surface
to define a path of movement, placing an object adjacent said
laminar flow of air, and regulating motion of said object along
said path of movement using said laminar flow of air.
12. A method as recited in claim 11, wherein said surface has a
curved portion and said regulating step includes turning an edge of
said object along said curved portion of said surface.
13. A method as recited in claim 12, wherein said turning is
performed on a leading edge of said object.
14. A method as recited in claim 12, wherein said turning step is
performed in accordance with a width of said object.
15. A method as recited in claim 11, wherein said step of directing
a laminar flow of air includes amplification of volume of air
forming said laminar flow.
16. A method as recited in claim 11, including a further step of
limiting propagation of noise from said laminar flow of air with
said object.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to object transport
and sorting systems and, more particularly, to object placement and
stacking structures at destination pockets of such systems.
[0003] 2. Description of the Prior Art
[0004] The transport of material and objects is an important
feature of many industrial activities, particularly when material
or objects must be moved on a large scale. Many such systems
include arrangements for sorting of objects or material in
accordance with properties thereof or indicia placed on the
objects. For example, large volumes of mail or packages which must
be transported to different locations must first be sorted in
accordance with addresses placed thereon in the course of being
transported to different locations in a sorting facility. Similar
systems and applications may be encountered in baggage handling in
airports and the like.
[0005] Such sorting of objects requires the objects to be handled
in sequence in order to provide selectivity of handling and
direction to various locations from which groups of objects that
can be commonly transported to another location. This requirement
generally implies that the objects must be transported at
relatively high speed in order to accommodate the volume of objects
which are presented. While it is possible to regulate the speed of
objects somewhat in a high volume sorting apparatus, it is not
generally possible to provide space to allow significant
deceleration of objects as they approach their final destination in
the sorting machinery. Therefore, as the object approaches a final
destination such as a sorting bin or a stacker apparatus (sometimes
referred to as a destination pocket or, simply, pocket) in the
sorting system, the deceleration must usually be quite abrupt and
often involves allowing the object to impact more or less violently
on a surface or barrier such as the side of a destination pocket in
a largely uncontrolled motion possibly including substantial
rebound and, at least, not allowing the deposited articles to be
placed in the destination pocket in an orderly fashion such as a
stack.
[0006] Orderly positioning of objects in a destination pocket,
often referred to as "neatness", "raggedness" (e.g. "left-edge
raggedness") or, more generally, "stack quality", is essential to
avoid jamming of the system and damage to the objects following
collisions between the trailing edge of an object and the leading
edge of another object sent to the same bin, often in very rapid
succession (e.g. as much as fifteen objects per second). Less than
optimal stack quality and objects that assume a tilted orientation,
in particular, present edges and surfaces and otherwise occupy a
portion of the volume of the pocket where collisions are likely.
Further, since these variations from an ideal stack are essentially
random, they are not readily resolved by machinery once they
occur.
[0007] For example, to improve the orderly placement of objects in
a destination pocket, several additional types of device have been
employed: one being of an auger type and another being a
pneumatically actuated pusher. An exemplary mechanism including
both of these known devices is shown in FIG. 5. (The depiction of
FIG. 5 is arranged to illustrate operation of the known devices in
a manner to facilitate comparison with the present invention and no
portion of FIG. 5 is admitted to be prior art in regard thereto.
Therefore, FIG. 5 has been designated as "Related Art".) An
incoming article or piece of mail is directed along plate 510 and
one edge of the article is engaged by auger 520 which seeks to turn
the article along the angled portion of plate 510. Once the article
is turned, it may be pushed into place in a stack by pusher plate
530, actuated by pneumatic actuator 540. Sorting of mail pieces is
accomplished by gates 550 which direct articles to one side or the
other of roller 560 as they are passed along a path defined by
rollers 570. It should also be appreciated that FIG. 5 illustrates
a portion of the sorting mechanism which forms a part of the
immediately downstream sorting mechanism and pocket.
[0008] Unfortunately, it has been found that collisions remain
likely to occur between the leading edge of an object and some
structure of the auger 520 or pusher 530, 540 as it manipulates
objects previously placed in the pocket while continuing to allow
rebound of a substantial number of objects which reduces the
effectiveness of the additional structures and continues to be a
source of collisions and jamming.
[0009] It has also been found that some widely used types of mail
envelopes, particularly a back-side vertically oriented,
end-flap-sealed C-5 envelope referred to as "Australia Post" which
is of very light weight and flexible has proven very difficult to
handle and is a major source of collisions, damage and jamming in
mail sorting system including systems equipped with one of the
additional auger or pusher device described above. In particular,
as one envelope of the Australia Post type or an edge thereof is
slid across another, an edge of one envelope will often engage an
incompletely sealed portion of the sealing flap of another,
preventing registration of envelopes in a stack or with the sides
of the destination pocket. Further, it has been found, particularly
in regard to the Australia Post envelope, that such auger and/or
pusher devices are a source of article or object damage as well as
a source of noise and particulates (e.g. cellulose paper dust) and
a potential source of injury to personnel.
[0010] Since objects such as mail envelopes are often essentially
"flown" into a destination pocket, and the importance of the
aerodynamics of the objects has been recognized and, occasionally,
exploited, it has been proposed to direct movement of objects with
air currents. However, operational costs can become prohibitive
when even moderate amounts of pressurized air at effective
velocities are required. It is generally considered that the number
of destination pockets required on many mail sorters would multiply
such air requirements beyond the realm of feasibility even if
relatively efficient arrangements could be designed. Further, any
such arrangement must accommodate both incoming objects and objects
previously deposited and exert control over such objects reliably
over multiple degrees of freedom while the orientation and motion
of the objects may vary widely to both establish and maintain good
stack quality. In other words, the amount and number of features of
control may be very limited consistent with other types of control
which may be desired. Other factors which also present problems in
the use of pressurized air are the generation of white noise and
the generation of particulates which may affect the operation of
the apparatus and possibly engender the potential for occupational
hazards.
SUMMARY OF THE INVENTION
[0011] Accordingly, the present invention provides an improved
arrangement for establishing and maintaining orderly placement of
objects in a destination pocket. The invention also provides for
improved, reliable and repeatable handling of particularly
light-weight and flexible objects such as the Australia Post
envelope with reduced noise, generation of particulates and injury
hazard, both to objects and operators. Further, the invention
provides consistent and reliable handling and stacking of object by
air flow while reducing the volume of high pressure and/or high
velocity air that is required.
[0012] In order to achieve these and other effects of the
invention, a stacker apparatus is provided comprising a plate
having a curved portion, nozzle or the like for producing a laminar
flow of air over the curved portion of the surface and directed
along a path of desired object movement, and an arrangement for
directing an object along the laminar flow of air whereby motion of
said object is regulated along the path of movement by the laminar
air flow.
[0013] In accordance with another aspect of the invention, a method
of controlling movement of an object is provided comprising steps
of directing a laminar flow of air along a surface to define a path
of movement, placing an object adjacent the laminar flow of air,
and regulating motion of said object along said path of movement
using said laminar flow of air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The foregoing and other objects, aspects and advantages will
be better understood from the following detailed description of a
preferred embodiment of the invention with reference to the
drawings, in which:
[0015] FIG. 1 is a top view of a stacker destination pocket in
accordance with the invention installed therein,
[0016] FIG. 2 is an oblique front view of the stacker in accordance
with the invention,
[0017] FIG. 3 schematically depicts an interaction of objects which
the invention principally seeks to avoid,
[0018] FIG. 4 is a top view of an alternative, variant form of the
stacker in accordance with the invention, and
[0019] FIG. 5 is a top view of a related mechanism over which the
present invention provides significant improvements.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
[0020] Referring now to the drawings, and more particularly to
FIGS. 1 and 2, there is shown a top view of a destination pocket
with the stacker in accordance with the invention installed therein
and a front oblique view of the stacker, respectively. The same
reference numerals will be used to indicated corresponding features
in both views.
[0021] The stacker 10 in accordance with the invention has no
moving parts and is generally placed in a fixed location in a
destination pocket in line with incoming mail pieces. However, it
is possible and may be desirable in some cases to provide some
degree of motion such as change of height above the bottom of the
destination pocket and/or rotation (in the directions indicated by
dashed arrows) in order to accommodate larger stacks of objects or
to maintain the object handling characteristics of the invention as
stack height increases.
[0022] The stacker 10 comprises a plate 20 with slightly curved
ends 30, 30'. The plate 20 can be formed easily and inexpensively
from any of a number of materials such as sheet metal or polymers.
The plate 20 is preferably substantially rigid but some flexibility
may be useful in absorbing some energy of incoming objects.
However, the position of the plate 20 should be well-controlled and
oscillation such as ringing from impact of objects should generally
be avoided. The curvature of end 30' is not at all critical to the
practice of the invention and need only accommodate some variation
of position of incoming objects 100 so that the objects do not
strike the edge of plate 20 but pass smoothly along it. In general,
objects will tend to move closely along the surface of plate 20 and
contact will generally be slight if at all since the air flow
between the object and the flat stationary plate will cause a
slight lowering of pressure by Bernoulli effect therebetween. Thus
the motion of an incoming object is generally well-controlled while
the object is relatively remote from stack 90.
[0023] However, if an object continues along this path defined by
the flat portion of plate 20 (and possibly rollers; an exemplary
clearance cut-out for which is depicted at 80), the edge of an
incoming object will impact at some point on the surface of a
previously stacked object at substantial speed. The friction
resulting from this action will generate particulate matter from
the surfaces of the objects. This particulate matter may accumulate
to cause malfunctioning of the sorter system or other apparatus in
the vicinity and/or reduce the environmental quality for personnel
operating the sorter system. Further, little energy will be
dissipated and the incoming object is likely to rebound from the
end of the destination pocket in a largely uncontrolled motion;
causing collisions with further incoming objects or at least
causing the stacking to be irregular.
[0024] A particularly intractable problem prior to the present
invention is illustrated in FIG. 3. If an object 110 placed on the
stack has some irregularity 110' such as an incompletely sealed
flap, as is presented by the "Australia Post" envelope 110 alluded
to above, or even an incompletely adhered stamp or the like on the
upper side of the object 110, as stacked, the impact of the edge of
an incoming object 120 can force the edge thereof under the
irregularity and cause damage thereto. More importantly in regard
to the stacking operation, the arresting of the incoming object 120
by the irregularity 110' prevents the proper placement of the
object 120 on the stack and actually tends to impede movement of
the object 120 from a position such that collisions are more likely
to occur. That is, when objects 110 and 120 are held together, as
shown, however tenuously, object 120 can settle onto object 110
only as air flows out from between them. Therefore, the trailing
edge of object 120 will remain close to the path of further
incoming objects for a longer time than would otherwise be the
case.
[0025] It should be appreciated that in order to avoid the scenario
depicted in FIG. 3, the leading edge of an incoming object 100 must
be turned slightly as it approaches the stack 90. A substantially
ideal action, achieved by the invention in a manner which will be
discussed in detail below is depicted in FIG. 1 at 100'. More
specifically, turning of the leading edge not only avoids direct
impact of an object 100 with stack 90 but also causes an overall
rotation of the object which tends to more quickly move the
trailing edge of the object from the path of a following incoming
object. Moreover, turning of the leading edge of the object allows
it to be directed to an arresting arrangement which can reduce or
avoid rebounding action and/or generation of particulates. Further,
in accordance with the invention, additional guidance may be
provided to the object 100 which will also assist in achieving and
maintaining the quality of stack 90.
[0026] The invention achieves these effects in a manner which
avoids mechanical contact with the object by utilizing pressurized
air while limiting the amount of pressurized air which is required
to do so. It can be appreciated from the top view of the invention
of FIG. 1 that these two criteria cannot be satisfied by
application of air to the trailing edge of incoming objects 100
since the air would necessarily be applied from a location at a
distance greater than the stack length (e.g. left to right in FIG.
1) away from the location at which the turning of the object edge
would be achieved. At the same time, providing pressurized air
between stack 90 and incoming object 100 would tend to impede
movement of object 100 out of the path of further incoming objects
100 and increase the likelihood of collisions, object damage, poor
stack quality and jamming of the sorter. In summary, a large volume
of air would be required at high pressure and high velocity to
achieve turning of the edge of an incoming objects and which may be
ineffective to achieve edge turning with sufficient rapidity while
other problems of stacking would be exacerbated.
[0027] The invention achieves extremely quick edge turning with a
small volume of air by introducing air between the object and plate
20 which also has additional advantageous effects as will be
described in detail below. Specifically, in accordance with a
preferred embodiment of the invention, plate 20 is divided along
its height prior (along the incoming object path) to the curvature
of an end portion 30 thereof. At this location, a curved region 45
is formed and a nozzle in the form of a very narrow elongated slot
40 (sometimes referred to as an air knife) is placed adjacent
thereto and preferably including an inclined edge or surface to
direct air thereover in close proximity to the curved region
45.
[0028] Thus a substantially laminar air flow regime is established
at curved region 45 and, further across and along curved portion
30. A slot 50 is also provided at the other side of the air knife
40 and the reduced pressure of air moving across region 45 causes
air to be drawn into slot 50, as indicated by arrow 50'. This
entrained air 50' greatly augments the volume of air flowing across
the curved portion 30 of plate 20 and the combination of an air
knife 40 and slot 50 thus functions as an air amplifier; greatly
reducing the amount of high pressure air required (which is
preferably further reduced by valves controlled by sensors at the
infeed end of plate 20 and/or the diverter control signals of the
sorter system). This augmented air flow follows the curved surface
30 of plate 20 and carries and guides the object 100 by the Coanda
effect until the air is allowed to exit at a grill 60 which is
preferably inclined to the air flow and object motion and
preferably arranged to support an object arresting surface such as
a mail stop 70 that defines an end of stack 90. The volume and
velocity of air from the air knife and from the air amplifier are
not critical and suitable values may be readily determined
theoretically or empirically in accordance with the range of weight
and dimensions of articles or objects to be stacked.
[0029] The location of the sensors or the timing of air control in
accordance with the diverter control signals of the sorter system
is preferably arranged such that the air knife acts only on the
leading edge of the article or object to achieve a turning effect.
The trailing edges thus "kicks out" from plate 20 to a greater or
lesser degree depending on the weight and stiffness of the
article.
[0030] The angled orientation of the grill 60 serves to deflect the
edge of incoming objects downward while absorbing energy therefrom
without causing damage or generation of any significant amount of
particulates. At the same time, the location of the grill directs
the air being exhausted from the stacker to carry and guide the
object toward the mail stop 70 to form a high quality stack 90. The
curved surface 30 thus controls the formation of vortices and
provides extremely laminar flow defining a well-behaved and
adaptive pneumatic envelope and movement path for the objects with
well-controlled pressure gradients formed and directed in a highly
predictable and repeatable manner to facilitate the direction,
velocity and inertial energy of incoming objects.
[0031] In this latter regard, it should be appreciated that the
incoming objects are substantially enclosed in the air flow between
the ambient air pressure and the reduced pressure along the curved
surface 30 where the air flow is accelerated. That is, the object
separates these two regions of different air flow and is
essentially held in place between them while the air flow along the
curved surface 30 establishes a movement path and, effectively,
"lubricates" the stacker surfaces adjacent to the objects; largely
avoiding contact between them and dramatically reducing production
of particulates. The effects, while somewhat similar to those
produced by shear forces and object motion upstream of the air
amplifier along plate 20, described above, will be dramatically
increased downstream of the air amplifier where the air flow is
accelerated. By the same token, forces which will be applied to the
incoming objects at various locations along the movement path will
conform the object motion to the air flow and the movement path
defined thereby. Thus the stacker in accordance with the invention
automatically adapts the handling forces applied to each object in
accordance with the direction, speed and inertia of the object.
That is, heavier objects having more inertia will be decelerated
and kinetic energy removed and dissipated while lighter objects are
effectively carried to the desired location on the stack 90.
[0032] This arrangement also limits production of white noise by
the reduction of the required volume of high pressure air.
Propagation of the relatively low level of noise produced is also
limited by the physical arrangement in accordance with the
invention. Noise production as well as high pressure air volume
requirements can also be further reduced, as a perfecting feature
of the invention, by dividing the air knife structure along its
width as indicated by bracket 45 at one or more locations and using
only the portion of the air knife as may generally correspond to
the height of an object as may be determined by appropriate sensors
or other expedients which will be apparent to those skilled in the
art. The use of a sensor and/or control signals from the sorter, as
alluded to above, also assures not only that the high pressure air
will be applied "on demand" to reduce the volume of high pressure
air required but also develops the above-described flow regimes
only when an object is adjacent the air knife or appropriate
portion thereof. The object thus forms an acoustic barrier which
contains the air amplifier behind it and essentially forms a sonic
control conduit along the object transport path.
[0033] Noise does not significantly propagate from slot 50 since
the air flow is in the opposite direction at substantial volume.
Residual noise is reflected from the object vertically and
horizontally away from the operator by the vents in grill 60. Since
the stacker in accordance with the invention has no moving parts,
there is no contribution of mechanical noise other than the
irreducible noise from the stacking of the objects themselves. Thus
the sonic pressure and audible noise can be maintained well below
industry limits.
[0034] In view of the foregoing, it is seen that the invention
provides the advantageous effects of adaptive control over delivery
and stacking of objects that can vary significantly in dimensions,
shape and weight while limiting contact with the objects while
greatly reducing high pressure air requirements and generation and
propagation of noise as well as generation of particulates. The air
flow and resulting vacuum is regulated upstream of the air
amplifier by the shear forces on the ambient air due to object
movement and the stationary plate 20 and much increased downstream
along the curved portion 30 to turn the object edges and regulate
the direction velocity and kinetic energy of objects in an adaptive
manner downstream of the air amplifier due to the Coanda effect to
achieve high quality stacking of the objects. The apparatus can be
easily and inexpensively fabricated and can be retrofit into
virtually any sorting or material handling structure where a
stacking function is desired.
[0035] It should be understood that the Coanda effect can be
applied to objects in other ways in variations of the invention
such as that shown in FIG. 4. In this embodiment of the invention,
objects are directed along in-feed plate 420 in much the same
manner as described above upstream of the air amplifier but are
allowed to impact on the stack. The air amplifier is formed by the
high pressure air flow 440 and the gap between the end of the
in-feed plate 420 and the stack. thus the Coanda effect is
developed in region 445 and the objects pulled into placed on the
stack thereby curved surface 430 is preferably formed to have a
plurality of finger-shaped portions and provides for convenience of
fabrication since features functioning as the air vent and the mail
stop structures of FIG. 1 can be integrally formed therewith.
However, since the objects are allowed to directly impact on the
stack, this embodiment is not preferred although most of the
effects of the invention except reduction of particulate production
can be achieved.
[0036] While the invention has been described in terms of a single
preferred embodiment, those skilled in the art will recognize that
the invention can be practiced with modification within the spirit
and scope of the appended claims. For example, while the invention
has been described in connection with a preferred vertical
orientation of generally flat objects and articles, it is clear
that the principles of the invention are applicable to operation in
other orientations and/or objects of other shapes.
* * * * *